Enabling Hibernation on older PCs

If for some reason you cant seem to use the Hibernation feature, see if the BIOS settings has something silly disabled.

[ source ]
Firstly, check if ACPI is currently enabled or not by...

1. Going to the the Device Manager window and expanding Computer.
2. If the Advanced Configuration and Power Interface (ACPI) PC option is not displayed, your computer does not support ACPI features.

Reboot and check your BIOS settings and check if anything is disabling ACPI or APM.